Article Cite This: Energy Fuels XXXX, XXX, XXX−XXX
pubs.acs.org/EF
Waste Polypropylene and Waste Cooking Oil As Feedstocks for an Alternative Component Containing Diesel Fuel Production Dániel Sági, Péter Solymosi, András Holló, Zoltán Varga, and Jenő Hancsók* Department of MOL Hydrocarbon and Coal Processing, University of Pannonia, Faculty of Engineering, Institute of Chemical and Process Engineering, P.O. Box: 158, H-8201 Veszprém, Hungary ABSTRACT: Nowadays the development and application of alternative fuels (including biofuels) are highly important for several reasons, e.g., protection of the environment and people’s health and achievement of sustainable development, etc. Diesel fuels are important in road transportation in the European Union and all over the world. So, it is necessary to develop alternative (bio)fuels for diesel engines. During the development of these alternative fuels, it is necessary to take into account that it does not endanger the cultivation of food and feed crops. According to the above-mentioned reasons, we studied the catalytic hydrogenation of mixtures of the middle distillates derived from thermal cracking of waste polypropylene (WPPCF) (5−30%), waste cooking oil (WCO) (20−45%), and straight-run gas oil (GO) (50%), on a sulfided NiMo/Al2O3 catalyst to produce diesel fuel. We investigated the effects of feedstock compositions and process parameters (T = 300−360 °C, LHSV = 1.0−3.0 h−1, P = 40 bar, hydrogen/feedstock = 400 N m3/m3) on the main product’s quality and yield. We concluded that good quality diesel fuel blending components with high alternative component content (approximately 50%) can be produced from feedstocks having 30/20% WPPCF, 20/30% WCO, and 50% GO at advantageous process parameters (T = 340−360 °C, LHSV = 1.0 h−1, P = 40 bar, hydrogen/feedstock = 400 N m3/m3). acids in themselves9,10,12 or in mixtures with conventional refinery streams11−14 to produce biogas oil. Besides the conversion of different waste-derived triglycerides (esters)/fatty acids, the use of plastic wastes for this purpose could also be a favorable solution. 322 million tons of plastic were produced in 2015 in the world (58 million tons in EU), and almost half of them were polyolefin, e.g., polyethylene (27%) and polypropylene (19%).15 Unfortunately, a huge amount of plastic waste (26 million tons in EU) is generated from them, and it is partially recycled (69% in EU).15 For this reason, a lot of researchers are investigating the recycling possibilities of waste plastics, including the fuel production from them, too. Most of the research groups investigated only the thermal or catalytic cracking of (waste) plastics for fuel production. These experiments are usually carried out in batch reactors at 300− 500 °C and at atmospheric pressure.16−18 The applicability of the liquid cracking products in internal combustion engines was also investigated, but their quality was usually much lower than the conventional, fossil diesel fuels.19,20 Therefore, it would be reasonable to study the quality improvement of these cracked products (e.g., by catalytic hydrogenation), but very little information is available about it in the free literature. Based on the results of the open literature, the middle distillates of thermal cracking of waste plastics as well as the waste esters (triglycerides)/fatty acids could be advantageous feedstocks for the production of alternative diesel fuel blending components. The catalytic hydrogenation of esters (triglycerides)/ fatty acids (from different sources) was studied in many articles, but information about the conversion (quality improvement) of
1. INTRODUCTION The World’s energy demand is increasing, and it is covered mainly with fossil fuels.1 It is important to replace the fossil fuels with alternative energy sources in even higher and higher ratio to decrease environmental pollution and the dependence on fossil fuels. The most widely used alternative fuels are biofuels (e.g., bioethanol, biodiesel) in road transportation.1 These biofuels mostly are food based, so the ratio of using them is going to be limited or decreased (e.g., in the European Union) in the future to protect the cultivation of food and feed crops.2,3 Furthermore, they have unfavorable indirect Land Use Change (iLUC) values. For this reason, it is necessary to investigate the usability of different wastes for fuel production. Diesel fuels are important in road transportation in the European Union (EU) and all over the World, especially in the transportation of goods. Also, the ratio of diesel fuels is getting even higher.4 For this reason, it is necessary to develop alternative fuels (e.g., biofuels) for diesel engines, too. Nowadays, the most widely used biocomponent of diesel fuels is biodiesel, which has many disadvantages: low thermal and oxidation stability,5 bad cold flow properties,6 lower energy content compared to fossil diesel fuels,7 etc. Due to the many disadvantages of biodiesel, it is important to make research and development works for producing new alternative (bio)fuels with better properties. The production and use of the so-called biogas oil could be an answer for the increasing demand of diesel fuels and their alternative components. The biogas oil8 is a mixture of gas oil boiling range n- and iso-paraffins, which are produced by the special hydrocracking (hydroconversion) of natural and waste esters (triglycerides) and fatty acids (e.g., waste cooking oil,9 waste animal fat,10 fatty acid byproduct).11 Several research groups have investigated the conversion of triglycerides (esters)/fatty © XXXX American Chemical Society
Received: December 13, 2017 Revised: February 7, 2018
A
DOI: 10.1021/acs.energyfuels.7b03937 Energy Fuels XXXX, XXX, XXX−XXX
Article
Energy & Fuels mixtures of middle distillates derived from thermal cracking of waste plastics and waste triglycerides (esters) to produce diesel fuel blending components has not been reported yet. This is why the aim of our experiments was to produce diesel fuel blending components from the mixtures of middle distillates of thermal cracking of waste plastics, waste triglycerides (esters), and crude oil derived, straight-run gas oil.
Table 3. Compositions of Feedstock Mixtures, Which Were Used for the Heterogeneous Hydrogenation Experiments
2. EXPERIMENTAL WORK
Table 1. Properties of Unrefined Gas Oil Fraction and the Middle Distillate from Thermal Cracking of Waste Polypropylene properties
GO
WPPCF
0.8338 8252 36.8 25.0 13.8 −19
